The primary objective of this study is to characterize the antioxidant effect of Vitamin E supplementation. To this end two novel in vivo markers of oxidative stress will be measured: 8-epi-PGF (2 alpha) and 8- oxodG. The specific objectives of the study are: i) to determine the optimum dose of vitamin E required to reach maximum antioxidant effect. ii) to establish the time course to reach maximal antioxidant effect iii) to establish the duration of the antioxidant effect following discontinuation of vitamin E iv) to compare the efficacy of two novel markers of oxidative stress.